Berthod C. auteur aut IRD Komorowski J.C. auteur aut IRD Gurioli L. auteur aut IRD Médard E. auteur aut IRD Bachèlery P. auteur aut IRD Besson P. auteur aut IRD Verdurme P. auteur aut IRD Chevrel Magdalena Oryaelle auteur aut IRD Di Muro A. auteur aut IRD Peltier A. auteur aut IRD Devidal J.L. auteur aut IRD Nowak S. auteur aut IRD Thinon I. auteur aut IRD Burckel P. auteur aut IRD Hidalgo S. auteur aut IRD Deplus C. auteur aut IRD Loubrieu B. auteur aut IRD Pierre D. auteur aut IRD Bermell S. auteur aut IRD Pitel-Roudat M. auteur aut IRD Réaud Y. auteur aut IRD Fouchard S. auteur aut IRD Bickert M. auteur aut IRD Le Friant A. auteur aut IRD Paquet F. auteur aut IRD Feuillet N. auteur aut IRD Jorry S.L. auteur aut IRD Fouquet Y. auteur aut IRD Rinnert E. auteur aut IRD Cathalot C. auteur aut IRD Lebas E. auteur aut IRD text journalArticle eng text/pdf reformatted digital access The 'Fani Maoré' eruption off the coasts of Mayotte has been intensively monitored by applying methods similar to those used for subaerial eruptions. Repeated high-resolution bathymetric surveys and dredging, coupled with petrological analyses of time-constrained samples, allowed tracking the evolution of magma over the whole submarine eruptive sequence. Indeed, after one year of direct ascent (Phase 1), basanitic magma switched to a different pathway that sampled a tephri-phonolitic subcrustal reservoir (Phase 2). Later, the magma pathway shifted again in the crust resulting in a new eruption site located 6 km northwest of the main edifice (Phase 3). The petrological signature of lava flows reveals both an evolution by fractional crystallization and syn-eruptive mixing with a tephri-phonolitic magma. We demonstrate that high-flux eruption of large volumes of basanitic magma from a deep-seated reservoir can interact with shallower reservoirs and remobilize eruptible magma. This has significant hazards implications with respect to the capacity of such large eruptions to reactivate shallow-seated inactive reservoirs from a transcrustal magmatic system that could be located potentially at a distance from the high-flux eruptive site. specialized MAYOTTE 064 354 S2 195-223 2023 1631-0713 https://www.documentation.ird.fr/hor/fdi:010088394 10.5802/crgeos.155 1631-0713 [F B010088394] https://www.documentation.ird.fr/hor/fdi:010088394 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2023-07/010088394.pdf IRD - Base Horizon / Pleins textes 2023-07-18 2026-06-12 fdi:010088394 fre